Electrolytic gas converter and electric equipment using the same

ABSTRACT

In an electrolytic gas converter for converting atmospheric moisture into ozone gas, oxygen gas or hydrogen gas, the electrolytic gas converter is provided with a unit for making control so that an electric current is supplied to the electrochemical device conjunctive body during a predetermined period of time after the start of the operation of gas conversion, the electric current being larger than that after the predetermined period of time passes. In addition, the control unit controls the current to flow periodically. Further, the electrolytic gas converter is provided with a unit for making control so that a predetermined constant current is supplied to the electrochemical device conjunctive body after the predetermined period of time passes since the operation of gas conversion is started.

BACKGROUND OF THE INVENTION

[0001] The present invention relates to an electrolytic gas converterbased on electrochemical reaction using a solid polymer electrolytemembrane, and more particularly relates to an electrolytic gasconverter, such as an ozone generator, an oxygen generator, a hydrogengenerator or a dehumidifier, in which a DC voltage is applied between ananode and a cathode opposed to each other through a solid polymerelectrolyte membrane so that atmospheric moisture is converted intoozone gas, oxygen gas or hydrogen gas in accordance with electrochemicalreaction.

[0002]FIG. 21 is a diagram showing the configuration of an ozonegenerator which is one of related-art electrolytic gas converters,disclosed in the Unexamined Japanese Patent Application Publication No.Hei 11-131276. In FIG. 21, an anode 1 has an anode catalyst layer on ananode substrate made of a conductive porous base material. A cathode 2has a cathode catalyst layer on a cathode substrate made of a conductiveporous base material. The anode 1 and the cathode 2 are disposed on thefront and back surfaces of a solid polymer electrolyte membrane 3, andbonded thereto by thermo compression. Thus, an electrochemical deviceconjunctive body 8 is formed. The reference numeral 4 represents ananode terminal provided on the anode 1; 5, a cathode terminal providedon the cathode 2; 6, a DC power supply; and 7, a connection wire forconnecting the DC power supply 6, the anode 1 and the cathode 2.

[0003] Incidentally, as the anode 1, for example, there is used an anodein which β-type or α-type lead dioxide is thinly electrodeposited on anexpanded metal substrate made of titanium and plated with platinum asundercoat. As the cathode 2, for example, there is used a cathode inwhich a solid polymer electrolyte obtained by liquefying carbon powdercarrying platinum fine particles is fixedly attached as binder onto aporous carbon fiber substrate.

[0004] Next, description will be made on the operation. For example,when a voltage of 3 V is applied to the electrochemical deviceconjunctive body 8 by the DC power supply 6, atmospheric moisture iselectrolyzed in the conjunction surface between the anode 1 and thesolid polymer electrolyte membrane 3 in accordance with electrochemicalreaction formulae (1) and (2). Thus, hydrogen ions are generated as soonas ozone gas, oxygen gas and electrons are generated.

2H₂O→O₂+4H⁺+4e  (1)

3H₂O→O₃+6H⁺+6e  (2)

[0005] The ozone gas and the oxygen gas generated thus flow out to theoutside air through the porous anode 1. On the other hand, the generatedhydrogen ions move to the cathode 2 through the solid polymerelectrolyte membrane 3. In the conjunction surface between the cathode 2and the solid polymer electrolyte membrane 3, the hydrogen ions reactwith oxygen gas in the air and the electrons introduced into the cathode2 through the connection wire 7 so as to generate water. The water flowsout to the outside air through the porous cathode 2.

[0006] Incidentally, when the electrochemical device conjunctive body 8is used for oxygen gas generation or dehumidification, that is, when theelectrolytic gas converter is an oxygen gas generator or a dehumidifier,for example, a porous expanded metal substrate made of titanium andplated with platinum is used as the anode 1 of the electrochemicaldevice conjunctive body 8. In this case, oxygen is generated from theanode while water is released from the back of the cathode.

[0007] When the electrochemical device conjunctive body 8 is used forhydrogen gas generation, that is, when the electrolytic gas converter isa hydrogen gas generator, for example, a porous expanded metal substratemade of titanium and plated with platinum is used as each of the anode 1and the cathode 2. In this case, hydrogen gas is generated in thecathode.

[0008] The related-art electrolytic gas converter is arranged asdescribed above. When the electrolytic gas converter is operatedintermittently in high humidity environment, the solid polymerelectrolyte membrane 3 retains excessive moisture after the operation ofgas conversion is suspended. When the operation of gas conversion isrestarted, the resistance of the electrochemical device conjunctive body8 is lowered significantly so that a voltage necessary for generation ofgas by electrochemical reaction cannot be ensured. Thus, there is aproblem that the gas generation of the electrochemical deviceconjunctive body 8 becomes unstable.

[0009] Particularly, in the case of ozone gas generation, when thevoltage applied to the electrochemical device conjunctive body 8(hereinafter referred to as “load voltage”) is lower than 3 V, ozonegeneration becomes unstable. Thus, there is a problem that the quantityof generated ozone gas is lowered significantly.

SUMMARY OF THE INVENTION

[0010] The invention is developed to solve these foregoing problems. Itis an object of the invention to obtain an electrolytic gas converter inwhich in intermittent operation in high humidity environment, thequantity of converted gas can be prevented from being loweredsignificantly at the start of the operation of gas conversion, and thequantity of converted gas can be kept stable during the operation of gasconversion.

[0011] In addition, it is another object of the invention to provideelectric equipment which has this electrolytic gas converter and inwhich the quantity of converted gas can be kept stable during theoperation of gas conversion in intermittent operation in high humidityenvironment.

[0012] According to the invention, there is provided a firstelectrolytic gas converter including: an electrochemical deviceconjunctive body having an anode and a cathode each having a catalystlayer provided on a substrate made of a conductive porous base material,and a solid polymer electrolyte membrane disposed between the anode andthe cathode, a DC voltage being applied to the electrochemical deviceconjunctive body so as to convert atmospheric moisture into ozone gas,oxygen gas or hydrogen gas; and a unit for making control so that anelectric current flows into the electrochemical device conjunctive bodyduring a predetermined period of time after start of operation of gasconversion, the electric current being larger than that after thepredetermined period of time passes.

[0013] According to the invention, there is provided a secondelectrolytic gas converter in which in the first electrolytic gasconverter, a unit is provided for making control so that an electriccurrent is made to flow into the electrochemical device conjunctive bodyperiodically during a predetermined period of time after start ofoperation of gas conversion, the electric current being larger than thatafter the predetermined period of time passes.

[0014] According to the invention, there is provided a thirdelectrolytic gas converter in which in the first electrolytic gasconverter, a unit is provided for making control so that a predeterminedconstant electric current flows into the electrochemical deviceconjunctive body after the predetermined period of time passes since thestart of operation of gas conversion.

[0015] According to the invention, there is provided a fourthelectrolytic gas converter including: an electrochemical deviceconjunctive body having an anode and a cathode each having a catalystlayer provided on a substrate made of a conductive porous base material,and a solid polymer electrolyte membrane disposed between the anode andthe cathode, a DC voltage being applied to the electrochemical deviceconjunctive body so as to convert atmospheric moisture into ozone gas,oxygen gas or hydrogen gas; and a unit for making control so that avoltage low enough or an electric current small enough not to convertthe moisture into the gas is applied or conducted to the electrochemicaldevice conjunctive body during suspension of operation of gasconversion.

[0016] According to the invention, there is provided a fifthelectrolytic gas converter in which in the fourth electrolytic gasconverter, a unit is provided for making control so that a predeterminedconstant electric current flows into the electrochemical deviceconjunctive body during the operation of gas conversion.

[0017] According to the invention, there is provided a sixthelectrolytic gas converter including: an electrochemical deviceconjunctive body having an anode and a cathode each having a catalystlayer provided on a substrate made of a conductive porous base material,and a solid polymer electrolyte membrane disposed between the anode andthe cathode, a DC voltage being applied to the electrochemical deviceconjunctive body so as to convert atmospheric moisture into ozone gas,oxygen gas or hydrogen gas; and a unit for making control so that anelectric current is made to flow into the electrochemical deviceconjunctive body in a case where a voltage applied to theelectrochemical device conjunctive body is lower than a predeterminedvoltage, the electric current being larger than in another case wherethe voltage is higher than the predetermined voltage.

[0018] According to the invention, there is provided a seventhelectrolytic gas converter in which in the sixth electrolytic gasconverter, a unit is provided for making control so that a predeterminedconstant electric current is made to flow into the electrochemicaldevice conjunctive body when a voltage applied to the electrochemicaldevice conjunctive body is not lower than a predetermined voltage.

[0019] According to the invention, there is provided an eighthelectrolytic gas converter in which in the first or sixth electrolyticgas converter, a unit is provided for making control so that a circuitconnected to the electrochemical device conjunctive body is releasedduring suspension of operation of gas conversion.

[0020] According to the invention, there is provided a ninthelectrolytic gas converter in which in the any one of the first througheighth electrolytic gas converters, the electrochemical deviceconjunctive body is used as an ozone generating device, an oxygengenerating device, a hydrogen generating device, or a dehumidifyingdevice.

[0021] According to the invention, there is provided first electricequipment having any one of the first through eighth electrolytic gasconverters.

BRIEF DESCRIPTION OF THE DRAWINGS

[0022]FIG. 1

[0023]FIG. 1 is a diagram for explaining a configuration of anelectrolytic gas converter according to Embodiment 1 of the invention.

[0024]FIG. 2

[0025]FIG. 2 is a diagram concerned with Embodiment 1 of the inventionand for explaining the operation of the electrolytic gas converteraccording to Embodiment 1.

[0026]FIG. 3

[0027]FIG. 3 is a diagram for explaining a configuration of anelectrolytic gas converter according to Embodiment 2 of the invention.

[0028]FIG. 4

[0029]FIG. 4 is a diagram for explaining a configuration of anelectrolytic gas converter according to Embodiment 3 of the invention.

[0030]FIG. 5

[0031]FIG. 5 is a diagram concerned with Embodiment 3 of the inventionand for explaining the operation of the electrolytic gas converteraccording to Embodiment 3.

[0032]FIG. 6

[0033]FIG. 6 is a diagram for explaining a configuration of anelectrolytic gas converter according to Embodiment 4 of the invention.

[0034]FIG. 7

[0035]FIG. 7 is a diagram for explaining a configuration of anelectrolytic gas converter according to Embodiment 5 of the invention.

[0036]FIG. 8

[0037]FIG. 8 is a diagram for explaining another configuration of anelectrolytic gas converter according to Embodiment 5 of the invention.

[0038]FIG. 9

[0039]FIG. 9 is a diagram for explaining a configuration of anelectrolytic gas converter according to Embodiment 6 of the invention.

[0040]FIG. 10

[0041]FIG. 10 is a diagram for explaining a configuration of anelectrolytic gas converter according to Embodiment 7 of the invention.

[0042]FIG. 11

[0043]FIG. 11 is a diagram for explaining another configuration of anelectrolytic gas converter according to Embodiment 7 of the invention.

[0044]FIG. 12

[0045]FIG. 12 is a diagram for explaining a configuration of anelectrolytic gas converter according to Embodiment 8 of the invention.

[0046]FIG. 13

[0047]FIG. 13 is a diagram for explaining a configuration of anelectrolytic gas converter according to Embodiment 9 of the invention.

[0048]FIG. 14

[0049]FIG. 14 is a diagram for explaining a configuration of anelectrolytic gas converter according to Embodiment 10 of the invention.

[0050]FIG. 15

[0051]FIG. 15 is a diagram concerned with Embodiment 10 of the inventionand for explaining the relationship between a current and a voltageflowing into an electrochemical device conjunctive body.

[0052]FIG. 16

[0053]FIG. 16 is a diagram for explaining a configuration of anelectrolytic gas converter according to Embodiment 11 of the invention.

[0054]FIG. 17

[0055]FIG. 17 is a diagram concerned with Embodiment 11 of the inventionand for explaining the relationship between a current and a voltageflowing into an electrochemical device conjunctive body.

[0056]FIG. 18

[0057]FIG. 18 is a diagram for explaining a configuration of anelectrolytic gas converter according to Embodiment 12 of the invention.

[0058]FIG. 19

[0059]FIG. 19 is a diagram concerned with Embodiment 12 of the inventionand for explaining the relationship between a current and a voltageflowing into an electrochemical device conjunctive body.

[0060]FIG. 20

[0061]FIG. 20 is a diagram for explaining a configuration of anelectrolytic gas converter according to Embodiment 13 of the invention.

[0062]FIG. 21

[0063]FIG. 21 is a diagram for explaining a configuration of arelated-art electrolytic gas converter.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0064] (Embodiment 1)

[0065] An ozone generator will be chiefly described below as anelectrolytic gas converter according to Embodiment 1 of the invention byway of example. FIG. 1 is a diagram for explaining the configuration ofthe electrolytic gas converter according to Embodiment 1 of theinvention.

[0066] In FIG. 1, the reference numeral 1 represents an anode having acatalyst layer provided on a substrate made of a conductive porous basematerial; 2, a cathode having a catalyst layer provided on a substratemade of a conductive porous base material; 3, a solid polymerelectrolyte membrane; 4, an anode terminal provided on the anode 1; 5, acathode terminal provided on the cathode 2; 6, a DC power supply; 8, anelectrochemical device conjunctive body formed by thermo compressionbonding of the anode 1 and the cathode 2 which are disposed on the frontand back surfaces of the solid polymer electrolyte membrane 3; 11, forexample, an NPN-type transistor; 12, an emitter of the transistor 11;13, abase; 14, a collector; 15, an electric current flowing between theemitter 12 and the base 13; 16, a collector current flowing into thecollector 14; and 17, a resistor. The electrochemical device conjunctivebody 8 is connected between the higher potential output side of the DCpower supply 6 and the collector 14 of the transistor 11, with theemitter 12 connected to the other output side of the DC power supply 6.In addition, the resistor 17 is connected between the higher potentialoutput side of the DC power supply 6 and the base 13 of the transistor11.

[0067] In this embodiment, a unit is constituted by the transistor 11and the resistor 17 so that the unit makes control to make apredetermined constant electric current flow into the electrochemicaldevice conjunctive body 8.

[0068] The reference numeral 102 represents a resistor which isconnected in parallel with the resistor 17 between the lower potentialoutput side of the DC power supply 6 and the base 13 of the transistor11. Thus, the resistor 102 constitutes a circuit A. The referencenumeral 101 represents a circuit (for example, a timer) having afunction to bring the circuit A into a closed state only for apredetermined time span. Working with the intermittent operation of theelectrochemical device conjunctive body 8, the operation to bring thecircuit A into the closed state is repeated only for the predeterminedtime span when the operation of gas conversion is restarted. Thereference numeral 103 represents an electric current flowing into thecircuit A.

[0069] In this embodiment, a unit is constituted by the resistor 102 andthe timer 101, so that the unit makes control to make an electriccurrent flow into the electrochemical device conjunctive body 8 during apredetermined period of time after the start of the operation of gasconversion, the electric current being larger than that after thepredetermined period of time passes.

[0070] In addition, a unit is constituted by the transistor 11, theresistors 17 and 102, and the timer 101, so that the unit makes controlin a manner such that an electric current larger than a predeterminedconstant electric current flows into the electrochemical deviceconjunctive body 8 during a predetermined period of time after the startof the operation of gas conversion, and then the predetermined constantelectric current flows.

[0071] Next, description will be made on the operation.

[0072] First, description will be made on the steady operation after apredetermined period of time passes since the operation of gasconversion is started. In the steady operation, the timer 101 is in anopened state. In the circuit of FIG. 1, the electric current 15 having avalue obtained by dividing the output voltage of the DC power supply 6chiefly by the resistance value of the resistor 17 flows between theemitter 12 and the base 13 of the transistor 11. This current becomesconstant without having any influence of the properties of theelectrochemical device conjunctive body 8 provided on the collector 14side of the transistor 11. Therefore, the constant current 16 obtainedby multiplying the current 15 flowing between the emitter 12 and thebase 13 by the amplification factor of the transistor 11 flows into thecollector 14. Thus, a constant current flows into the electrochemicaldevice conjunctive body 8. Incidentally, the value of the currentsupplied to the electrochemical device conjunctive body 8 can be set byproperly selecting the transistor 11, the voltage value of the DC powersupply 6 and the resistance value of the resistor 17.

[0073] Thus, the circuit of FIG. 1 allows a constant current to flowinto the electrochemical device conjunctive body 8. Even if the outsideair environment such as humidity changes on a large scale, theelectrochemical device conjunctive body 8 can obtain a stable quantityof converted gas without generating excessive gas.

[0074] Next, description will be made on the time when the operation ofgas conversion is started. In the circuit of FIG. 1, when theelectrochemical device conjunctive body 8 is operated intermittently torestart the operation of gas conversion, the timer 101 is operated tobring the circuit A into the closed state only for a predetermined timespan. Then, a base current in which the current flowing through theresistor 17 and the current 103 flowing through the resistor 102 arelinked up flows into the base 13 of the transistor 11. As a result, alarger current flows into the electrochemical device conjunctive body 8than that when the base current is only a current flowing through theresistor 17. After that, when the timer 101 switches to an opened state,only the current 15 flowing through the resistor 17 flows into the base13 of the transistor 11. As described above, a predetermined constantcurrent flows into the electrochemical device conjunctive body 8 byproperly selecting the transistor 11, the voltage value of the DC powersupply 6 and the resistance value of the resistor 17.

[0075] Thus, according to the circuit of FIG. 1, in the intermittentoperation in the high humidity environment, the electric current flowinginto the electrochemical device conjunctive body 8 can be increased onlyfor a predetermined time span after the start of the operation of gasconversion. The load voltage on the electrochemical device conjunctivebody 8 can be enhanced so that the quantity of generated ozone can beprevented from being lowered significantly at the start of the operationof gas conversion. In addition, after that, a predetermined constantelectric current smaller than the current at the start of the operationof gas conversion can be supplied. Even if there is a change in theenvironmental conditions such as humidity, the quantity of generatedozone can be obtained efficiently and stably without generatingexcessive gas.

[0076] Next, description will be made on the operation of thisembodiment along a specific example while comparison is made with acircuit shown in FIG. 2 which does not have the circuit A. In theconstant current circuit shown in FIG. 2 which does not have the circuitA, setting is done so that the voltage (V0) of the DC power supply 6 is5 V, and the predetermined constant current flowing into theelectrochemical device conjunctive body 8 (the electrochemical reactionarea formed by the anode and the cathode opposed to each other is 2.4cm²) is 25 mA/cm². An operating cycle of 2-hour running and 22-hoursuspension is repeated in the high humidity environment of thetemperature 25° C. and the relative humidity 90% so as to generateozone. In this case, the load voltage (Vd) on the electrochemical deviceconjunctive body 8 is lower than 2 V at the start of the operation ofgas conversion, and the quantity of generated ozone is loweredsignificantly.

[0077] On the other hand, in the circuit of FIG. 1 according to thisembodiment, the timer 101 is set so that the circuit A would be broughtinto the closed state only for 5 minutes after the start of theoperation of gas conversion. The resistor 102 is set so that the current103 flowing into the circuit A would be twice as large as the currentflowing through the resistor 17. As a result, a constant current of 75mA/cm² flowed into the electrochemical device conjunctive body 8 for 5minutes after the start of the operation of gas conversion. After that,the timer 101 switched to the opened state so that only the currentflowing through the resistor 17 flowed into the base 13 of thetransistor 11. Thus, a constant current of 25 mA/cm² flowed into theelectrochemical device conjunctive body 8.

[0078] As a result, in the intermittent operation in the high humidityenvironment, the quantity of generated ozone is prevented from lowingsignificantly at the start of the operation of gas conversion, while astable quantity of generated ozone could be obtained during theoperation of gas conversion. In addition, since a predetermined constantcurrent (25 mA/cm²) is supplied in this embodiment, the quantity ofgenerated ozone could be kept efficient and more stable withoutgenerating excessive gas even if there is a change in the outside airenvironment such as humidity.

[0079] Incidentally, although FIG. 1 shows the case where an NPNtransistor is used as the transistor 11, a PNP transistor may be used.In this case, there is some difference in how to connect, but similareffects can be obtained.

[0080] (Embodiment 2)

[0081] Although description in Embodiment 1 is made on the case wherethe transistor 11 is used, similar effects can be obtained using aresistor in place of the transistor 11.

[0082]FIG. 3 is a diagram for explaining the configuration of anelectrolytic gas converter according to Embodiment 2 of the invention.In FIG. 3, the reference numerals 105 and 106 represent resistorsrespectively. The resistor 106 is connected in series between the anodeof the DC power supply 6 and the anode 1 of the electrochemical deviceconjunctive body 8. That is, there is shown a characteristic as follows.When a large current attempts to flow into the electrochemical deviceconjunctive body 8, the load voltage (Vd) on the electrochemical deviceconjunctive body 8 is lowered by the resistor 106. On the contrary, whenthe current flowing into the electrochemical device conjunctive body 8is lowered, the load voltage (Vd) on the electrochemical deviceconjunctive body 8 is increased by the resistor 1106. Accordingly, bysetting the resistor 106 having a proper resistance value in advance, acurrent outputted from the DC power supply 6 to the electrochemicaldevice conjunctive body 8 is made constant. Thus, generation ofexcessive ozone is prevented even if the humidity of the outside air ishigh.

[0083] In this embodiment, the circuit A constituted by the timer 101and the resistor 105 is connected in parallel with the resistor 106 inthe circuitry. A unit is constituted by the resistor 105 and the timer101 so that the unit makes control to make a current flow for apredetermined period of time after the start of the operation of gasconversion, the current being larger than that after the predeterminedperiod of time passes.

[0084] Next, description will be made on the operation. In the circuitof FIG. 3, the electrochemical device conjunctive body 8 is operatedintermittently. When the operation of gas conversion is restarted, thetimer 101 is operated to bring the circuit into the closed state onlyfor a predetermined time span. In this case, an electric current has avalue which is obtained in a manner so that the voltage obtained bysubtracting the load voltage (Vd) on the electrochemical deviceconjunctive body 8 from the output voltage (V0) of the DC power supply 6is divided by the parallel resistance constituted by the resistors 105and 106. The thus obtained electric current flows into theelectrochemical device conjunctive body 8. After that, when the timer101 switches to the opened state, a current has a value obtained in amanner so that the voltage obtained by subtracting the load voltage (Vd)on the electrochemical device conjunctive body 8 from the output voltage(V0) of the DC power supply 6 is divided by the resistance value of theresistor 106. The thus obtained current flows into the electrochemicaldevice conjunctive body 8.

[0085] Here, the resistance values of the resistors 105 and 106 are setso that the current flowing into the electrochemical device conjunctivebody 8 will be approximately 75 mA/cm² when the timer 101 is in theclosed state, while the current flowing into the electrochemical deviceconjunctive body 8 will be approximately 25 mA/cm² when the timer 101 isin the opened state.

[0086] In this case, because the change of the load voltage on theelectrochemical device conjunctive body 8 has a complicated relationshipto the current, the stability of the quantity of generated ozone isinferior to that in the circuit of FIG. 1. However, according to thecircuit of FIG. 3, there is an advantage that the number of parts in thecircuit is small so that the cost is inexpensive.

[0087] (Embodiment 3)

[0088]FIG. 4 is a diagram for explaining the configuration of anelectrolytic gas converter according to Embodiment 3 of the invention.

[0089] In FIG. 4, the reference numeral 31 represents an AC input suchas a commercial power source; 32, a rectifying circuit for constitutinga full-wave rectifying circuit or the like; 33, a voltage smoothingcapacitor; 34, a charge quantity limiting capacitor; and 35, a voltagelimiting Zener diode. The charge quantity limiting capacitor 34 isconnected in series between the AC input 31 and the rectifying circuit32. The voltage smoothing capacitor 33 and the voltage limiting Zenerdiode 35 are connected in parallel with the electrochemical deviceconjunctive body 8.

[0090] In this embodiment, a unit is constituted by the rectifyingcircuit 32, the capacitors 33 and 34, and the voltage limiting Zenerdiode 35, so that the unit makes control to make a predeterminedconstant current flow into the electrochemical device conjunctive body8.

[0091] The reference numeral 112 represents a capacitor, which isconnected in parallel with the charge quantity limiting capacitor 34between the AC input 31 and the rectifying circuit 32. Thus, a circuit Bis constituted. The reference numeral 111 represents a circuit (such asa timer) having a function to bring the circuit B into the closed stateonly for a predetermined time span. Working with the intermittentoperation of the electrochemical device conjunctive body 8, theoperation to bring the circuit B into the closed state is repeated onlyfor the predetermined time span when the operation of gas conversion isrestarted.

[0092] In this embodiment, a unit is constituted by the capacitor 112and the timer 111, so that the unit makes control to make an electriccurrent flow into the electrochemical device conjunctive body 8 during apredetermined period of time after the start of the operation of gasconversion, the electric current being larger than that after thepredetermined period of time passes.

[0093] Next, description will be made on the operation.

[0094] First, description will be made on the steady operation after thepredetermined period of time passes since the operation of gasconversion is started. In the steady operation, the timer 111 is in theopened state. In the circuit of FIG. 4, when the AC input 31 is a 100 Vcommercial power source, an effective voltage of about 100 V is appliedto the opposite ends of the charge quantity limiting capacitor 34 atintervals of 50 or 60 cycles. The quantity of charges corresponding tothe change of voltage is transmitted to the rectifying circuit 32.Therefore, a current supplied to the rectifying circuit 32 is determinedby the capacitance value of the charge quantity limiting capacitor 34.The current flowing into the electrochemical device conjunctive body 8can be kept constant by setting the capacitance value of the chargequantity limiting capacitor 34 to be constant. At this time, byconnecting the voltage limiting Zener diode 35 in parallel with theelectrochemical device conjunctive body 8, the voltage applied to theelectrochemical device conjunctive body 8 is restrained from beingexcessive.

[0095] Thus, according to the circuit of FIG. 4, the number of parts isreduced even in the case of an AC input, and a constant current can bemade to flow into the electrochemical device conjunctive body 8. Thus,the electrochemical device conjunctive body 8 can obtain a stablequantity of converted gas without generating excessive gas even if thereis a great change in the outside air environment such as humidity.

[0096] Next, description will be made on the time when the operation ofgas conversion is started. In the circuit of FIG. 4, when theelectrochemical device conjunctive body 8 is operated intermittently torestart the operation of gas conversion, the timer 111 is operated tobring the circuit into the closed state for a predetermined time span.In this case, a constant current determined by the parallel capacitancevalue of the capacitors 34 and 112 is supplied to the electrochemicaldevice conjunctive body 8. After that, when the timer 111 switches tothe opened state, a constant current determined by the capacitance valueof only the capacitor 34 is supplied to the electrochemical deviceconjunctive body 8.

[0097] Thus, according to the circuit of FIG. 4, a constant currentflowing into the electrochemical device conjunctive body 8 can beincreased only for a predetermined period of time after the start of theoperation of gas conversion. Thus, the load voltage on theelectrochemical device conjunctive body 8 can be enhanced so that thequantity of generated gas can be prevented from being loweredsignificantly at the start of the operation of gas conversion. Inaddition, after that, a predetermined constant electric current smallerthan the current at the start of the operation of gas conversion can besupplied. Even if there is a change in the environmental conditions suchas humidity, the quantity of generated ozone can be obtained efficientlyand stably without generating excessive gas.

[0098] Next, description will be made on the operation of thisembodiment along a specific example while comparison is made with acircuit shown in FIG. 5 which does not have the circuit B. In theconstant current circuit shown in FIG. 5 which does not have the circuitB, the capacitance value of the capacitor 34 is set so that the AC inputis 100 V at 60 cycles, the voltage applied to the electrochemical deviceconjunctive body 8 by the voltage limiting Zener diode 35 is 5 V, andthe constant current flowing into the electrochemical device conjunctivebody 8 (the electrochemical reaction area formed by the anode and thecathode opposed to each other is 2.4 cm²) is 25 mA/cm². An operatingcycle of 2-hour running and 22-hour suspension is repeated in the highhumidity environment of the temperature 25° C. and the relative humidity90% so as to generate ozone. In this case, the load voltage on theelectrochemical device conjunctive body 8 is lower than 2 V at the startof the operation of gas conversion, and the quantity of generated ozoneis lowered significantly.

[0099] On the other hand, in the circuit of FIG. 4 according to thisembodiment, the timer 111 is set so that the circuit B would be in theclosed state for 5 minutes after the start of the operation of gasconversion. The charge capacitance values of the capacitors 34 and 112are set so that the current flowing into the electrochemical deviceconjunctive body 8 would be approximately 75 mA/cm² when the timer 111is in the closed state, while the predetermined constant value flowinginto the electrochemical device conjunctive body 8 would beapproximately 25 mA/cm² when the timer 111 is brought into the openedstate.

[0100] As a result, the quantity of generated ozone is prevented frombeing lowered significantly at the start of the operation of gasconversion, while a stable quantity of generated ozone could be obtainedduring the operation of gas conversion. In addition, since apredetermined constant current (25 mA/cm²) is made to flow in thisembodiment, the quantity of generated ozone could be kept efficient andmore stable without generating excessive gas even if there is a changein the outside air environment such as humidity.

[0101] Incidentally, in the respective Embodiments 1 to 3, descriptionis made on the case where the timers 101 and 111 are in the closed stateonly for 5 minutes. However, the duration of the closed state of thetimers 101 and 111 may be longer or shorter. In this case, when theduration of the closed state of the timers 101 and 111 is longer, thetime taken to reach a predetermined voltage becomes longer, but there isan advantage that the current made to flow into the electrochemicaldevice conjunctive body 8 can be reduced. On the other hand, when theduration of the closed state of the timers 101 and 111 is shorter, it isnecessary to increase the current supplied to the electrochemical deviceconjunctive body 8. However, there is an advantage that the time takento reach a predetermined voltage becomes shorter.

[0102] In addition, in the respective Embodiments 1 to 3, description ismade on the case where there is provided a unit for making control sothat a constant current larger than a predetermined constant current ismade to flow into the electrochemical device conjunctive body 8 for apredetermined period of time after the start of the operation of gasconversion. However, it will go well if the current is larger than thepredetermined constant current, and the current does not have to beconstant.

[0103] Furthermore, description is made on the case where there isprovided a unit for making control so that a predetermined constantcurrent is supplied after the predetermined period of time passes sincethe start of the operation of gas conversion. However, when there islittle change in the environmental conditions such as humidity, the unitfor making control so that a constant current is supplied may be notrequired.

[0104] (Embodiment 4)

[0105]FIG. 6 is a diagram for explaining the configuration of anelectrolytic gas converter according to Embodiment 4 of the invention.

[0106] In FIG. 6, the reference numeral 300 represents a timer which canrepeat a conduction state and a non-conduction state in a predeterminedcycle within a predetermined operating time (for example, a timerconstituted by a timer for determining the predetermined operating time,a vibrator for determining the cycle with in the predetermined operatingtime, and a vibrator for determining the conduction duration in thepredetermined cycle).

[0107] In this embodiment, the timer 300 which can repeat a conductionstate and a non-conduction state in a predetermined cycle within apredetermined operating time is used in place of the timer 101 whichbrings the circuit A into the closed state only for a predetermined timespan as described in Embodiment 1. This embodiment is different fromEmbodiment 1 at such a point, but the other configuration is similar tothat in FIG. 1 shown in Embodiment 1.

[0108] In this embodiment, a unit is constituted by the resistor 102 andthe timer 300, so that the unit makes control to make an electriccurrent flow into the electrochemical device conjunctive body 8periodically for a predetermined period of time after the start of theoperation of gas conversion, the electric current being larger than thatafter the predetermined period of time passes.

[0109] In addition, a unit is constituted by the transistor 11, theresistors 17 and 102, and the timer 300 so that the unit makes controlto supply a predetermined constant current to the electrochemical deviceconjunctive body 8 after a current larger than the predeterminedconstant current is supplied periodically for a predetermined period oftime after the start of the operation of gas conversion.

[0110] Next, description will be made on the operation, chieflyconcerning the different point from Embodiment 1. In the circuit of FIG.6, when the electrochemical device conjunctive body 8 is operatedintermittently to restart the operation of gas conversion, the timer 300is operated so that the circuit A repeats a cycle of a closed state andan opened state with a predetermined time span for a predeterminedperiod of time. At this time, when the circuit A is in the closed state,a base current in which a current flowing through the resistor 17 and acurrent 103 flowing through the resistor 102 are linked up flows intothe base 13 of the transistor 11. As a result, a larger current flowsinto the electrochemical device conjunctive body 8 than that when thebase current is only a current flowing through the resistor 17. On theother hand, when the circuit A is in the opened state, only a current 15flowing through the resistor 17 flows into the base 13 of the transistor11. As a result, a large current and a small current flow into theelectrochemical device conjunctive body 8 periodically during theoperation of the timer 300. After that, when the timer 300 gets intosuspension (opened state), the current flowing into the base 13 of thetransistor 11 is only the current 15 flowing through the resistor 17.Thus, a predetermined constant current flows into the electrochemicaldevice conjunctive body 8 by properly selecting the transistor 11, thevoltage value of the DC power supply 6 and the resistance value of theresistor 17.

[0111] Thus, according to the circuit of FIG. 6, in the intermittentoperation in the high humidity environment, a current flowing into theelectrochemical device conjunctive body 8 can be increased periodicallyonly for a predetermined time span since the operation of gas conversionis started. Thus, the quantity of generated gas is prevented from beinglowered significantly at the start of the operation of gas conversion.In addition, after that, a predetermined constant current smaller thanthe current at the start of the operation of gas conversion can besupplied. Even if there is a change in the environmental conditions suchas humidity, the quantity of generated ozone can be obtained efficientlyand stably without generating excessive gas.

[0112] Further, in this embodiment, the current flowing into theelectrochemical device conjunctive body 8 is increased periodically onlyfor a predetermined time span since the operation of gas conversion isstarted. Thus, there can be also obtained an effect that the quantity ofgenerated gas can be controlled for the predetermined time span morecarefully than that when a constant current is supplied during apredetermined time span as described in Embodiment 1.

[0113] Next, description will be made on the operation of thisembodiment along a specific example while comparison is made with thecase shown in FIG. 2 which does not have the circuit A. In the constantcurrent circuit shown in FIG. 2 which does not have the circuit A,setting is done so that the voltage (V0) of the DC power supply 6 is 5V, and a predetermined constant current flowing into the electrochemicaldevice conjunctive body 8 (the electrochemical reaction area formed bythe anode and the cathode opposed to each other is 2.4 cm²) is 25mA/cm². An operating cycle of 2-hour running and 22-hour suspension isrepeated in the high humidity environment of the temperature 25° C. andthe relative humidity 90% so as to generate ozone. In this case, theload voltage (Vd) on the electrochemical device conjunctive body 8 islower than 2 V at the start of the operation of gas conversion, and thequantity of generated ozone is lowered significantly.

[0114] On the other hand, in the circuit of FIG. 6 according to thisembodiment, for example, setting is done so that the timer 300 wouldoperate for 30 minutes after the start of the operation of gasconversion, while a cycle in which the circuit A is in the closed statefor 2 minutes and in the opened state for 8 minutes would be repeatedthree times. At this time, when the circuit A is in the closed state, aconstant current of 75 mA/cm² flowed into the electrochemical deviceconjunctive body 8. When the circuit A is in the opened state, aconstant current of 25 mA/cm² flowed. After the timer 300 stopped itsoperation when 30 minutes passes, the current flowing into the base 13of the transistor 11 is the current flowing only through the resistor17. Thus, a constant current of 25 mA/cm² flowed into theelectrochemical device conjunctive body 8.

[0115] As a result, in the intermittent operation in the high humidityenvironment, the quantity of generated gas is prevented from beinglowered significantly at the start of the operation of gas conversion.In addition, during the operation of gas conversion, even if there is achange in the outside air environment such as humidity, the quantity ofgenerated ozone could be kept efficient and stable without generatingexcessive gas.

[0116] Incidentally, in the above embodiment, description is made on thecase where the timer 300 which could repeat a conduction state and anon-conduction state in a predetermined cycle within a predeterminedoperating time is used in the electrolytic gas converter according toEmbodiment 1 shown in FIG. 1, in place of the timer 101 for bringing thecircuit A into the closed state only for a predetermined time span.However, the timer 300 which can repeat a conduction state and anon-conduction state in a predetermined cycle within a predeterminedoperating time may be used in the electrolytic gas converter accordingto Embodiment 2 or 3 shown in FIG. 3 or 4, in place of the timer 101 or111 for bringing the circuit A into the closed state only for apredetermined time span. Also in this case, similar effects can beobtained.

[0117] (Embodiment 5)

[0118]FIG. 7 is a diagram for explaining the configuration of anelectrolytic gas converter according to Embodiment 5 of the invention.

[0119] In FIG. 7, the reference numerals 121 and 122 represent switchesrespectively; 123, a constant voltage circuit for generating a constantvoltage; and 124 and 125, resistors respectively.

[0120] In this embodiment, a unit is constituted by the switches 121 and122, the constant voltage circuit 123, and the resistors 124 and 125 sothat the unit makes control in a manner such that a voltage low enoughor an electric current small enough not to generate ozone (not toconvert moisture into gas) is applied or conducted to theelectrochemical device conjunctive body 8 during the suspension ofoperation of gas conversion.

[0121] In addition, a unit is constituted by a transistor 11 andresistors 17 and 124 so that the unit makes control to supply apredetermined constant current to the electrochemical device conjunctivebody 8 during the operation of gas conversion.

[0122] Furthermore, a unit is constituted by the transistor 11, theresistors 17, 124 and 125, the switches 121 and 122, and the constantvoltage circuit 123, so that the unit makes control in a manner suchthat a constant current is supplied to the electrochemical deviceconjunctive body 8 during the operation of gas conversion, while avoltage low enough or an electric current small enough not to generateozone (not to convert moisture into gas) is applied or conducted to theelectrochemical device conjunctive body 8 during the suspension ofoperation of gas conversion.

[0123] Next, description will be made on the operation. In the circuitof FIG. 7, first when both the switches 121 and 122 are brought into theclosed state at the time of the suspension of the operation of gasconversion of the electrochemical device conjunctive body 8, a voltagesupplied from the constant voltage circuit 123 is applied to theelectrochemical device conjunctive body 8 during the suspension of theoperation of gas conversion. At this time, the voltage supplied from theconstant voltage circuit 123 is set to a voltage low enough not togenerate ozone. Thus, a small current flows into the electrochemicaldevice conjunctive body 8.

[0124] Next, when both the switches 121 and 122 are brought into theopened state in order to restart the operation of gas conversion of theelectrochemical device conjunctive body 8, the voltage supply from theconstant voltage circuit 123 to the electrochemical device conjunctivebody 8 is suspended. Thus, a predetermined constant current flowsthrough the transistor 11 in the same manner as in the circuit shown inFIG. 2.

[0125] In such a manner, according to the circuit of FIG. 7, a voltagelow enough not to generate ozone (not to convert moisture into gas) isapplied during the suspension of the operation of gas conversion. Thus,a small current flows into the electrochemical device conjunctive body 8so that the solid polymer electrolyte membrane 3 of the electrochemicaldevice conjunctive body 8 is prevented from retaining excessivemoisture. Accordingly, when the operation of gas conversion isrestarted, a constant current can be made to flow into theelectrochemical device conjunctive body 8 in the state where the loadvoltage on the electrochemical device conjunctive body 8 is preventedfrom being lowered significantly. As a result, in the intermittentoperation in the high humidity environment, the quantity of generatedozone is prevented from being lowered significantly at the start of theoperation of gas conversion. On the other hand, during the operation ofgas conversion, the quantity of generated ozone can be obtainedefficiently and stably without generating excessive gas even if there isa change in the environmental conditions such as humidity.

[0126] Next, description will be made on the operation of thisembodiment along a specific example. Incidentally, the conditions of theintermittent operation and the conditions of the outside air environmentare similar to those in Embodiment 1. In the circuit of FIG. 7, when theelectrochemical device conjunctive body 8 is in the suspension of theoperation of gas conversion, both the switches 121 and 122 are broughtinto the closed state so that a voltage of 1.5 V is supplied from theconstant voltage circuit 123 to the electrochemical device conjunctivebody 8. At that time, a current ranging from 10 mA/cm² to 15 mA/cm²flowed into the electrochemical device conjunctive body 8, but thegeneration of ozone is not recognized.

[0127] Next, the switches 121 and 122 are brought into the opened statein order to start the operation of gas conversion of the electrochemicaldevice conjunctive body 8. Thus, a constant current of 25 mA/cm² is madeto flow through the transistor As a result, the quantity of generatedozone is prevented from being lowered significantly at the start of theoperation of gas conversion, while a stable quantity of generated ozonecould be obtained during the operation of gas conversion. In addition,since a predetermined constant current (25 mA/cm²) is made to flowduring the operation of gas conversion, the quantity of generated ozonecould be kept efficient and more stable without generating excessive gaseven if there is a change in the outside air environment such ashumidity.

[0128] Incidentally, a low voltage of, for example, 1.5 V is suppliedfrom the constant voltage circuit 123 to the electrochemical deviceconjunctive body 8 during the suspension of the operation of gasconversion in FIG. 7. However, as shown in FIG. 8, a constant voltagediode 127 may be used in place of the constant voltage circuit 123.

[0129] In this case, the resistor 124 is set so that a current rangingfrom 10 mA/cm² to 15 mA/cm² will flow into the electrochemical deviceconjunctive body 8 when the switch 121 is in the closed state, while aconstant current of 25 mA/cm² will flow into the electrochemical deviceconjunctive body 8 when the switch 121 is in the opened state.

[0130] In the circuit of FIG. 8, the constant voltage diode 127 isdesigned to be made conductive if the switch 121 is brought into theclosed state during the suspension of the operation of gas conversion,and, for example, the voltage exceeds 1.5 V. Thus, a current rangingfrom 10 mA/cm² to 15 mA/cm² can be made to flow into the electrochemicaldevice conjunctive body 8 while the voltage is clamped to be 1.5 V.Next, when the operation of gas conversion is restarted, the switch 121is brought into the opened state. Thus, a constant current of 25 mA/cm²can be made to flow into the electrochemical device conjunctive body 8through the transistor 11. In such a manner, according to the circuit ofFIG. 8, effects similar to those in the circuit of FIG. 7 can beobtained with a simple circuit.

[0131] In addition, although an example using the constant voltage diode127 is shown in FIG. 8, a Zener diode making conduction with a constantvoltage similar to that in the diode 127 may be used. Also in this case,similar effects can be obtained.

[0132] (Embodiment 6)

[0133] Although description in Embodiment 5 is made on the case wherethe transistor 11 is used, similar effects can be also obtained when aresistor is used in place of the transistor 11.

[0134]FIG. 9 is a diagram for explaining the configuration of anelectrolytic gas converter according to Embodiment 6 of the invention.In FIG. 9, the reference numeral 128 represents a resistor.

[0135] A resistor 128 is connected in series between the anode of the DCpower supply 6 and the anode 1 of the electrochemical device conjunctivebody 8. That is, there is shown a characteristic as follows. When alarge current attempts to flow into the electrochemical deviceconjunctive body 8, the load voltage (Vd) on the electrochemical deviceconjunctive body 8 is lowered by the resistor 128. On the contrary, whenthe current flowing into the electrochemical device conjunctive body 8is lowered, the load voltage (Vd) on the electrochemical deviceconjunctive body 8 is increased by the resistor 128. Accordingly, bysetting the resistor 128 having a proper resistance value in advance, acurrent supplied from the DC power supply 6 to the electrochemicaldevice conjunctive body 8 is made constant. Thus, generation ofexcessive ozone is prevented even if the humidity of the outside air ishigh.

[0136] In this embodiment, in the circuitry, a switch 122 is disposedbetween the resistor 128 and the electrochemical device conjunctive body8, and a circuit constituted by a switch 121 and a constant voltagecircuit 123 is connected in parallel with the electrochemical deviceconjunctive body 8. A unit is constituted by the switches 121 and 122and the constant voltage circuit 123, so that the unit makes control ina manner such that a voltage low enough or an electric current smallenough not to generate ozone (not to convert moisture into gas) isapplied or conducted to the electrochemical device conjunctive body 8during the suspension of operation of gas conversion.

[0137] Next, description will be made on the operation. In the circuitof FIG. 9, when the switches 121 and 122 are brought into the closedstate and the opened state respectively at the time of the suspension ofthe operation of gas conversion of the electrochemical deviceconjunctive body 8, there is no supply from the DC power supply 6 and avoltage supplied from the constant voltage circuit 123 is applied to theelectrochemical device conjunctive body 8. Incidentally, when thevoltage supplied from the constant voltage circuit 123 is set to avoltage low enough not to generate ozone, for example, to a voltage of1.5 V, a small current ranging from 10 mA/cm² to 15 mA/cm² flows intothe electrochemical device conjunctive body 8 so that the load voltageon the electrochemical device conjunctive body 8 is prevented from beinglowered significantly, in the same manner as in the case of FIG. 7.

[0138] Next, when the switches 121 and 122 are brought into the openedstate and the closed state respectively in order to restart theoperation of gas conversion of the electrochemical device conjunctivebody 8, the voltage supply from the constant voltage circuit 123 to theelectrochemical device conjunctive body 8 is suspended. Thus, a currentflows from the DC power supply 6 through the resistor 128 to theelectrochemical device conjunctive body 8. Incidentally, the resistancevalue of the resistor 128 is set so that the current flowing into theelectrochemical device conjunctive body 8 is approximately 25 mA/cm².

[0139] In this case, the change of the load voltage on theelectrochemical device conjunctive body 8 is not proportional to thecurrent but complicated. Thus, the stability of the quantity ofgenerated ozone is inferior to that in the circuit of FIG. 7. Accordingto the circuit of FIG. 9, however, there is an advantage that the numberof parts in the circuit is reduced so that the cost is reduced.

[0140] (Embodiment 7)

[0141]FIG. 10 is a diagram for explaining the configuration of anelectrolytic gas converter according to Embodiment 7 of the invention.

[0142] In FIG. 10, the reference numerals 131 and 132 represent switchesrespectively. The switch 132 is put into the opened state when theswitch 131 is in the closed state, while the switch 132 is put into theclosed state when the switch 131 is in the opened state. The referencenumeral 133 represents a constant voltage circuit.

[0143] In this embodiment, a unit is constituted by the switches 131 and132 and the constant voltage circuit 133, so that the unit makes controlin a manner such that a voltage low enough or an electric current smallenough not to generate ozone (not to convert moisture into gas) isapplied or conducted to the electrochemical device conjunctive body 8during the suspension of operation of gas conversion.

[0144] In addition, a unit is constituted by the rectifying circuit 32,the capacitors 33 and 34, and the voltage limiting Zener diode 35, sothat the unit makes control to supply a predetermined constant currentto the electrochemical device conjunctive body 8 during the operation ofgas conversion.

[0145] Next, description will be made on the operation. In the circuitof FIG. 10, when the switches 131 and 132 are brought into the closedstate and the opened state respectively at the time of the suspension ofthe operation of gas conversion of the electrochemical deviceconjunctive body 8, there is no voltage supply from the AC power source31 and a voltage supplied from the constant voltage circuit 133 isapplied to the electrochemical device conjunctive body 8 in thesuspension of the operation of gas conversion. At this time, the voltagesupplied from the constant voltage circuit 133 is set to a voltage lowenough not to generate ozone. Thus, a small current flows into theelectrochemical device conjunctive body 8.

[0146] Next, when the switches 131 and 132 are brought into the openedstate and the closed state respectively at the start of the operation ofgas conversion of the electrochemical device conjunctive body 8, thevoltage supply from the constant voltage circuit 133 to theelectrochemical device conjunctive body 8 is suspended. Thus, apredetermined constant current determined by the capacitor 34 issupplied during the operation of gas conversion.

[0147] In such a manner, according to the circuit of FIG. 10, a voltagelow enough not to generate ozone is applied during the suspension of theoperation of gas conversion so that a small current flows into theelectrochemical device conjunctive body 8. Accordingly, a constantcurrent can be supplied to the electrochemical device conjunctive body 8in the state where the load voltage on the electrochemical deviceconjunctive body 8 is prevented from being lowered significantly. As aresult, the quantity of generated ozone is prevented from being loweredsignificantly at the start of the operation of gas conversion. Inaddition, during the operation of gas conversion, the quantity ofgenerated ozone can be obtained efficiently and stably withoutgenerating excessive gas even if there is a change in the environmentalconditions such as humidity.

[0148] Next, description will be made on the operation of thisembodiment along a specific example while comparison is made with thecircuit shown in FIG. 5 which does not have the switches 131 and 132 andthe constant voltage circuit 133. Incidentally, the conditions of theintermittent operation and the conditions of the outside air environmentare similar to those in Embodiment 1 or 2. In the constant currentcircuit shown in FIG. 5 which does not have the switches 131 and 132 andthe constant voltage circuit 133, the capacitance value of the capacitor34 is set so that the AC input is 100 V at 60 cycles, the voltageapplied to the electrochemical device conjunctive body 8 by the voltagelimiting Zener diode 35 is 5 V, and a constant current flowing into theelectrochemical device conjunctive body 8 is 25 mA/cm². In this case,the load voltage on the electrochemical device conjunctive body 8 islower than 2 V at the start of the operation of gas conversion, and thequantity of generated ozone is lowered significantly.

[0149] On the other hand, in the circuit of FIG. 10 according to thisembodiment, the switches 131 and 132 are brought into the closed stateand the opened state respectively at the time of the suspension of theoperation of gas conversion of the electrochemical device conjunctivebody 8. Thus, a voltage of 1.5 V is supplied from the constant voltagecircuit 133 to the electrochemical device conjunctive body 8. At thistime, a small current ranging from 10 mA/cm² to 15 mA/cm² flowed intothe electrochemical device conjunctive body 8, but the generation ofozone is not recognized.

[0150] Next, the switches 131 and 132 are brought into the opened stateand the closed state respectively in order to start the operation of gasconversion of the electrochemical device conjunctive body 8. The voltagesupply from the constant voltage circuit 133 to the electrochemicaldevice conjunctive body 8 is suspended. Thus, a constant current of 25mA/cm² determined by the capacitor 34 is supplied.

[0151] As a result, the quantity of generated ozone is prevented frombeing lowered significantly at the start of the operation of gasconversion. On the other hand, during the operation of gas conversion, astable quantity of generated ozone could be obtained. In addition, sincea predetermined constant current (25 mA/cm²) is supplied in thisembodiment, the quantity of generated ozone could be kept efficient andmore stable without generating excessive gas even if there is a changein the outside air environment such as humidity.

[0152] Incidentally, in FIG. 10, a low voltage, for example, 1.5 V issupplied to the electrochemical device conjunctive body 8 by theconstant voltage circuit 133 during the suspension of the operation ofgas conversion. However, as shown in FIG. 11, a constant voltage diode137 may be used in place of the constant voltage circuit 133. In FIG.11, the reference numeral 134 represents a capacitor disposed inparallel with the capacitor 34, constituting a circuit B together withthe switch 132.

[0153] In this case, the capacitance value of the capacitor 34 is set sothat a current ranging from 10 mA/cm² to 15 mA/cm² will be supplied tothe electrochemical device conjunctive body 8 by the capacitor 34. Inaddition, the capacitance value of the capacitor 134 is set so that aconstant current of 25 mA/cm² will be supplied to the electrochemicaldevice conjunctive body 8 by the parallel capacitance of the capacitors34 and 134.

[0154] In the circuit of FIG. 11, the diode 137 is designed to makeconduction if the voltage exceeds 1.5 V by way of example when theswitches 131 and 132 are brought in the closed state and the openedstate respectively during the suspension of the operation of gasconversion. Thus, a current ranging from 10 mA/cm² to 15 mA/cm² can besupplied to the electrochemical device conjunctive body 8 while thevoltage is clamped to be 1.5 V. Next, when the operation of gasconversion is restarted, the switches 131 and 132 are brought into theopened state and the closed state respectively. Thus, a constant currentof 25 mA/cm² can be supplied to the electrochemical device conjunctivebody 8 by the parallel capacitance of the capacitors 34 and 134.

[0155] In such a manner, according to the circuit of FIG. 11, effectssimilar to those in the circuit of FIG. 10 can be also obtained withoutusing the constant voltage circuit 133.

[0156] In addition, although the case using the constant voltage diode137 is shown in FIG. 11, a Zener diode making conduction with a constantvoltage similar to that in the diode 137 may be used. Also in this case,similar effects can be obtained.

[0157] In the respective Embodiments 5 to 7, description is made on thecase where a voltage of 1.5 V is applied to the electrochemical deviceconjunctive body 8 during the suspension of the operation of gasconversion. However, the voltage is not limited to this value, but itwill go well if the voltage is low enough not to result in convertingmoisture into gas. In the case of an ozone generator, it is desired thatthe voltage is lower than 2 V. In this case, it is desired that acurrent smaller than 20 mA/cm² is supplied to the electrochemical deviceconjunctive body 8.

[0158] (Embodiment 8)

[0159]FIG. 12 is a diagram for explaining the configuration of anelectrolytic gas converter according to Embodiment 8 of the invention.

[0160] In FIG. 12, the reference numeral 141 represents a switch; 142,an amplifier; 143, a comparator; 144 and 145, resistors; 146, aninverter; and 147 and 148, resistors.

[0161] In this embodiment, a unit is constituted by the resistors 145,147 and 148, the switch 141, the amplifier 142, the comparator 143 andthe inverter 146, so that the unit makes control to supply an electriccurrent to the electrochemical device conjunctive body 8 in the casewhere a voltage applied to the electrochemical device conjunctive body 8is lower than a predetermined voltage, the electric current being largerthan that in the case where the voltage is higher than the predeterminedvoltage.

[0162] In addition, a unit is constituted by the transistor 11 and theresistors 17 and 144 so that the unit makes control to supply apredetermined constant current to the electrochemical device conjunctivebody 8.

[0163] Furthermore, a unit is constituted by the transistor 11, theresistors 17, 144, 145, 147 and 148, the switch 141, the amplifier 142,the comparator 143 and the inverter 146, so that the unit makes controlto supply a predetermined constant current to the electrochemical deviceconjunctive body 8 in the case where a voltage applied to theelectrochemical device conjunctive body 8 is higher than a predeterminedvoltage, and to supply an electric current larger than the predeterminedconstant current to the electrochemical device conjunctive body 8 whenthe voltage applied to the electrochemical device conjunctive body 8 islower than the predetermined voltage.

[0164] Here, the amplifier 142 obtains a difference between two inputsignals supplied to its input terminals, and amplifies the difference.The comparator 143 compares the output of the amplifier 142 with areference voltage VRef. When the output value of the amplifier 142 isnot lower than the reference voltage VRef, an output signal of thecomparator 143 becomes an L (low) level to thereby bring the switch 141into the closed state. On the other hand, when the output value of theamplifier 142 is lower than the reference voltage VRef, the outputsignal of the comparator 143 becomes an H (high) level to thereby bringthe switch 141 into the opened state. Incidentally, the referencevoltage VRef is a voltage corresponding to a predetermined load voltageon the electrochemical device conjunctive body 8.

[0165] Next, description will be made on the operation. In FIG. 12, whenthe electrochemical device conjunctive body 8 is operated intermittentlyto restart the operation of gas conversion in the high humidityenvironment, the load voltage on the electrochemical device conjunctivebody 8 becomes lower than the reference voltage VRef, for example, 2.5V. Thus, the output of the comparator 143 becomes the H (high) level,and the switch 141 is brought into the opened state. Accordingly, a basecurrent 15 obtained by dividing the DC power supply 6 substantially bythe sum of the resistance value of the resistor 17 and the resistancevalue of the resistor 144 flows into the base 13 of the transistor 11.At this time, the resistance values of the resistors 17 and 144 are setso that a constant current flowing into the electrochemical deviceconjunctive body 8 will be, for example, 75 mA/cm².

[0166] After that, when the load voltage on the electrochemical deviceconjunctive body 8 increases to exceed 2.5 V, the output signal of thecomparator 143 becomes the L (low) level so that the switch 141 isbrought into the closed state. When the switch 141 is brought into theclosed state, a part of the base current 15 is bypassed through theresistor 145 and the switch 141. At this time, setting is done inadvance so that a constant current of, for example, 25 mA/cm² will flowinto the electrochemical device conjunctive body 8.

[0167] Incidentally, the inverter 146 and the resistor 148 are providedto prevent the level of the output signal of the comparator 143 fromchanging again after it changes once. That is, once the output of thecomparator 143 becomes the H (high) level, the inverter 146 serves toreduce the minus-side input of the comparator 143 to be lower than 2.5V.

[0168] In such a manner, according to the circuit of FIG. 12, in theintermittent operation in the high humidity environment, significantreduction in the quantity of generated gas at the start of the operationof gas conversion is prevented with precision. In addition, a stablequantity of generated ozone can be obtained during the operation of gasconversion. In addition, in this embodiment, a predetermined constantcurrent (25 mA/cm²) is supplied when the voltage applied to theelectrochemical device conjunctive body is not lower than apredetermined voltage. Accordingly, the quantity of generated ozonecouldbe kept efficient andmore stablewithout generating excessive gaseven if there is a change in the outside air environment such ashumidity.

[0169] (Embodiment 9)

[0170]FIG. 13 is a diagram for explaining the configuration of anelectrolytic gas converter according to Embodiment 9 of the invention.

[0171] In FIG. 13, the reference numeral 151 represents a switch; and152, a capacitor. A comparator 143, an inverter 146 and resistors 147and 148 operate equivalently to those in Embodiment 8 shown in FIG. 12.In addition, when the output signal of the comparator 143 becomes the L(low) level, the switch 151 is brought into the opened state. On theother hand, when the output signal of the comparator 143 becomes the H(high) level, the switch 151 is brought into the closed state. Inaddition, the capacitance of the capacitor 34 is set so that the valueof a current flowing into the electrochemical device conjunctive body 8will be a predetermined constant current value when the switch 151 is inthe opened state.

[0172] In this embodiment, a unit is constituted by the capacitor 152,the switch 151, the comparator 143, the inverter 146, and the resistors147 and 148, so that the unit makes control to supply an electriccurrent to the electrochemical device conjunctive body 8 in the casewhere a voltage applied to the electrochemical device conjunctive body 8is lower than a predetermined voltage, the electric current being largerthan that in the case where the voltage is higher than the predeterminedvoltage.

[0173] In addition, a unit is constituted by the rectifying circuit 32,the capacitors 33 and 34, and the voltage limiting Zener diode 35, sothat the unit makes control to supply a predetermined constant currentto the electrochemical device conjunctive body 8.

[0174] Furthermore, a unit is constituted by the rectifying circuit 32,the capacitors 33, 34 and 152, the voltage limiting Zener diode 35, theswitch 151, the comparator 143, the inverter 146, and the resistors 147and 148, so that the unit makes control to supply a predeterminedconstant current to the electrochemical device conjunctive body 8 in thecase where a voltage applied to the electrochemical device conjunctivebody 8 is not lower than a predetermined voltage, and to supply anelectric current larger than the predetermined constant current to theelectrochemical device conjunctive body 8 in the case where the voltageapplied to the electrochemical device conjunctive body 8 is lower thanthe predetermined voltage.

[0175] Next, description will be made on the operation. In the circuitof FIG. 13, when the electrochemical device conjunctive body 8 isoperated intermittently to restart the operation of gas conversion, theload voltage on the electrochemical device conjunctive body 8 becomeslower than the reference voltage VRef, for example, 2.5 V. Thus, theoutput of the comparator 143 becomes the H (high) level, and the switch151 is brought into the closed state. Accordingly, a constant currentdetermined by the parallel capacitance values of the capacitors 34 and152 flows into the electrochemical device conjunctive body 8. At thistime, the capacitance values of the capacitors 34 and 152 are set sothat a current of, for example, 75 mA/cm² will flow into theelectrochemical device conjunctive body 8.

[0176] After that, when the load voltage on the electrochemical deviceconjunctive body 8 increases to be not lower than 2.5 V, the outputsignal of the comparator 143 becomes the L (low) level so that theswitch 151 is brought into the opened state. At this time, setting isdone so that a constant current determined only by the capacitor 34, forexample, 25 mA/cm² will flow into the electrochemical device conjunctivebody 8.

[0177] In such a manner, according to the circuit of FIG. 13, in theintermittent operation in the high humidity environment, significantreduction in the quantity of generated gas at the start of the operationof gas conversion is prevented with precision. In addition, a stablequantity of generated ozone can be obtained. In addition, in thisembodiment, a predetermined constant current (25 mA/cm²) is suppliedwhen the voltage applied to the electrochemical device conjunctive bodyis not lower than a predetermined voltage. Accordingly, the quantity ofgenerated ozone could be kept efficient and more stable withoutgenerating excessive gas even if there is a change in the outside airenvironment such as humidity.

[0178] (Embodiment 10)

[0179]FIG. 14 is a diagram for explaining the configuration of anelectrolytic gas converter according to Embodiment 10 of the invention.

[0180] In FIG. 14, the reference numeral 18 represents a resistor havinga resistance value R1; and 19, a constant voltage diode which allows anelectric current to be conducted when the voltage is not lower than aspecified voltage, that is, an operating voltage (Vz). In addition, aportion C is a constant current circuit constituted by a DC power supply6, a transistor 11 and a resistor 17.

[0181] In this embodiment, a unit is constituted by the resistor 18 andthe constant voltage diode 19 (a portion D), so that the unit makescontrol to supply an electric current to the electrochemical deviceconjunctive body 8 in the case where a voltage applied to theelectrochemical device conjunctive body 8 is lower than a predeterminedvoltage, the electric current being larger than that in the case wherethe voltage is higher than the predetermined voltage.

[0182] In addition, a unit is constituted by the transistor 11 and theresistor 17 so that the unit makes control to supply a predeterminedconstant current to the electrochemical device conjunctive body 8.

[0183] Furthermore, a unit is constituted by the transistor 11, theresistors 17 and 18, and the constant voltage diode 19, so that the unitmakes control to supply a predetermined constant current to theelectrochemical device conjunctive body 8 in the case where a voltageapplied to the electrochemical device conjunctive body 8 is not lowerthan a predetermined voltage, and to supply an electric current largerthan the predetermined constant current to the electrochemical deviceconjunctive body 8 in the case where the voltage applied to theelectrochemical device conjunctive body 8 is lower than thepredetermined voltage.

[0184] Next, description will be made on the operation. In the circuitof FIG. 14, when a load voltage Vd on the electrochemical deviceconjunctive body 8 is lower than a specified voltage at the start of theoperation of gas conversion, the constant voltage diode 19 is broughtinto the closed state. Thus, a current flows through the electrochemicaldevice conjunctive body 8 and the resistor 18 to the constant voltagediode 19 in this order. At this time, a current having the followingcurrent value flows into the electrochemical device conjunctive body 8.That is, the load voltage (Vd) on the electrochemical device conjunctivebody 8 and the voltage (Vz) of the constant voltage diode 19 aresubtracted from the voltage (V0) of the power supply 6. The voltageobtained thus is divided by the resistance value (R1) of the resistor18. The current value obtained thus is added to the value of theconstant current generated by the constant current circuit in theportion C. Thus, the value of the current flowing into theelectrochemical device conjunctive body 8 is obtained. Accordingly, bysetting the resistance value (R1) of the resistor 18 properly, as shownin FIG. 15, a current larger than the predetermined constant currentgenerated by the constant current circuit in the portion C can besupplied to the electrochemical device conjunctive body 8 when the loadvoltage (Vd) on the electrochemical device conjunctive body 8 becomeslower than a predetermined voltage.

[0185] After that, when the load voltage (Vd) on the electrochemicaldevice conjunctive body 8 increases to be not lower than the specifiedvoltage, the constant voltage diode 19 is brought into the opened state.Thus, only the constant current circuit in the portion C operates. Atthis time, a current 15 has a value obtained by dividing the DC outputvoltage (VO) of the DC power supply 6 chiefly by the resistance value ofthe resistor 17. The thus obtained current 15 flows between the emitter12 and the base 13 of the transistor 11 in the same manner as in thecase of Related Art Technique 1. Thus, a predetermined constant currentflows into the electrochemical device conjunctive body 8.

[0186] In such a manner, according to the circuit of FIG. 14, when theload voltage on the electrochemical device conjunctive body 8 is lowerthan a predetermined voltage, a current larger than a predeterminedconstant current can be supplied to the electrochemical deviceconjunctive body 8 as shown in FIG. 15. As a result, the load voltage onthe electrochemical device conjunctive body 8 can be enhanced so thatsignificant reduction in the quantity of generated gas at the start ofthe operation of gas conversion is prevented. In addition, apredetermined constant current can be supplied to the electrochemicaldevice conjunctive body 8 when the load voltage on the electrochemicaldevice conjunctive body 8 is not lower than the predetermined voltage.Accordingly, the quantity of generated ozone can be obtained efficientlyand stably.

[0187] Next, description will be made on the operation of thisembodiment along a specific example while comparison is made with thecircuit shown in FIG. 2 which does not have the portion D. Incidentally,the conditions of the intermittent operation and the conditions of theoutside air environment are similar to those in Embodiment 1 or 2. Inthe circuit of FIG. 14, the DC output voltage (V0) of the DC powersupply 6 is set to 5 V, the operating voltage (Vz) of the constantvoltage diode 19 is set to 2.5 V, and the resistance value of theresistor 18 is set to 5 Ω.

[0188] In this case, when the load voltage on the electrochemical deviceconjunctive body 8 is lower than the operating voltage (Vz) of theconstant voltage diode 19, for example, 2 V, a current of 75 mA/cm²flowed into the electrochemical device conjunctive body 8. Even at thestart of the operation of gas conversion, the voltage of theelectrochemical device conjunctive body 8 exceeded 2 V, so that thequantity of generated ozone is prevented from being loweredsignificantly.

[0189] After that, when the load voltage on the electrochemical deviceconjunctive body 8 increased to be not lower than 2.5 V, the constantvoltage diode 19 is brought into the opened state. Thus, only theconstant current circuit in the portion C operated so that a constantcurrent of 25 mA/cm² flowed into the electrochemical device conjunctivebody 8. Accordingly, a stable quantity of generated ozone is obtained.

[0190] In such a manner, according to the circuit of FIG. 14, in theintermittent operation in the high humidity environment, when the loadvoltage on the electrochemical device conjunctive body 8 is lower than apredetermined voltage, a current larger than a predetermined constantcurrent can be supplied to the electrochemical device conjunctive body8. As a result, the load voltage on the electrochemical deviceconjunctive body 8 can be enhanced so that significant reduction in thequantity of generated gas at the start of the operation of gasconversion is prevented. In addition, after that, a predeterminedconstant current smaller than that at the start of the operation of gasconversion can be supplied to the electrochemical device conjunctivebody 8. Accordingly, a stable quantity of generated ozone can beobtained during the operation of gas conversion. In addition, in thisembodiment, a predetermined constant current (25 mA/cm²) is supplied tothe electrochemical device conjunctive body when the voltage applied tothe electrochemical device conjunctive body is not lower than apredetermined voltage. Accordingly, the quantity of generated ozone canbe kept efficient and more stable without generating excessive gas evenif there is a change in the outside air environment such as humidity.

[0191] Incidentally, although an example using the constant voltagediode 19 is shown in FIG. 14, a Zener diode making conduction with aconstant voltage similar to that in the diode 19 may be used. Also inthis case, similar effects can be obtained.

[0192] (Embodiment 11)

[0193]FIG. 16 is a diagram for explaining the configuration of anelectrolytic gas converter according to Embodiment 11 of the invention.

[0194] In FIG. 16, the reference numerals 50 and 51 represent resistors;52, a constant voltage diode which makes conduction with a voltage notlower than a specified operating voltage (Vz); 53, a transistor; and 54,a diode. In addition, a portion E is a constant current circuit, whichis the same as the circuit shown in FIG. 5.

[0195] In this embodiment, a unit is constituted by the resistors 50 and51, the constant voltage diode 52, the transistor 53 and the diode 54,so that the unit makes control to supply an electric current to theelectrochemical device conjunctive body 8 in the case where a voltageapplied to the electrochemical device conjunctive body 8 is lower than apredetermined voltage, the electric current being larger than that inthe case where the voltage is higher than the predetermined voltage.

[0196] In addition, a unit is constituted by the rectifying circuit 32,the capacitors 33 and 34, and the voltage limiting Zener diode 35, sothat the unit makes control to supply a predetermined constant currentto the electrochemical device conjunctive body 8.

[0197] Furthermore, a unit is constituted by the rectifying circuit 32,the capacitors 33 and 34, the voltage limiting Zener diode 35, theresistors 50 and 51, the constant voltage diode 52, the transistor 53and the diode 54, so that the unit makes control to supply apredetermined constant current to the electrochemical device conjunctivebody 8 in the case where a voltage applied to the electrochemical deviceconjunctive body 8 is not lower than a predetermined voltage, and tosupply an electric current larger than the predetermined constantcurrent to the electrochemical device conjunctive body 8 in the casewhere the voltage applied to the electrochemical device conjunctive body8 is lower than the predetermined voltage.

[0198] Next, description will be made on the operation. In the circuitof FIG. 16, when the operating voltage (Vz) of the constant voltagediode 52 is, for example, set to 2.5 V, the load voltage on theelectrochemical device conjunctive body 8 is lower than 2.5 V at thestart of the operation of gas conversion. Accordingly, the constantvoltage diode 52 is brought into the opened state. Thus, a currentoutputted from the circuit E through the resistor 50 is supplied to theelectrochemical device conjunctive body 8 through the diode 54 inaddition to a current through the transistor 53. Accordingly, as shownin FIG. 17, as the load voltage on the electrochemical deviceconjunctive body 8 is lower, the current flowing into theelectrochemical device conjunctive body 8 increases.

[0199] After that, when the load voltage on the electrochemical deviceconjunctive body 8 increases to be not lower than 2.5 V, the constantvoltage diode 52 is brought into the closed state. Thus, only thecurrent through the transistor 53 flows into the electrochemical deviceconjunctive body 8 so that the load voltage on the electrochemicaldevice conjunctive body 8 becomes substantially constant. At the sametime, the value of the current flowing into the electrochemical deviceconjunctive body 8 also becomes substantially constant so that a stablequantity of generated ozone can be obtained.

[0200] In such a manner, according to the circuit of FIG. 16, when theload voltage on the electrochemical device conjunctive body 8 is lowerthan a predetermined voltage, a current larger than a predeterminedconstant current can be supplied to the electrochemical deviceconjunctive body 8 as shown in FIG. 17. As a result, the load voltage onthe electrochemical device conjunctive body 8 can be enhanced so thatsignificant reduction in the quantity of generated gas at the start ofthe operation of gas conversion is prevented. In addition, apredetermined constant current can be supplied to the electrochemicaldevice conjunctive body 8 when the load voltage on the electrochemicaldevice conjunctive body 8 is not lower than the predetermined voltage.Accordingly, a stable quantity of generated ozone can be obtained duringthe operation of gas conversion. In addition, in this embodiment, apredetermined constant current is supplied to the electrochemical deviceconjunctive body when the voltage applied to the electrochemical deviceconjunctive body is not lower than a predetermined voltage. Accordingly,the quantity of generated ozone can be kept efficient and more stablewithout generating excessive gas even if there is a change in theoutside air environment such as humidity.

[0201] (Embodiment 12)

[0202]FIG. 18 is a diagram for explaining the configuration of anelectrolytic gas converter according to Embodiment 12 of the invention.

[0203] In FIG. 18, the reference numeral 36 represent a resistor; and37, a constant voltage diode which makes conduction with a voltage notlower than a specified voltage (Vz). In addition, a portion E is aconstant current circuit, which is the same as the circuit shown in FIG.5. A portion F is a circuit added in accordance with this embodiment.

[0204] In this embodiment, a unit is constituted by the rectifyingcircuit 32, the capacitors 33 and 34, the voltage limiting Zener diode35, the resistor 36, and the constant voltage diode 37, so that the unitmakes control to supply an electric current to the electrochemicaldevice conjunctive body 8 in the case where a voltage applied to theelectrochemical device conjunctive body 8 is lower than a predeterminedvoltage, the electric current being larger than that in the case wherethe voltage is higher than the predetermined voltage.

[0205] Next, description will be made on the operation. In the circuitof FIG. 18, when the load voltage (Vd) on the electrochemical deviceconjunctive body 8 is lower than the specified voltage, the constantvoltage diode 37 is brought into the opened state. Thus, a constantcurrent determined by the capacitor 34 flows into the electrochemicaldevice conjunctive body 8. After that, when the load voltage on theelectrochemical device conjunctive body 8 increases to be not lower thanthe specified voltage, the constant voltage diode 37 is brought into theclosed state. Thus, the current is split to flow through the resistor 36and the constant voltage diode 37 in this order. Accordingly, thecurrent flowing into the electrochemical device conjunctive body 8decreases gradually with a predetermined voltage, that is, the operatingvoltage (Vz) of the constant voltage diode 37 as a border, as shown inFIG. 19. At this time, the split current value decreases in proportion(the inclination is determined by the resistance value of the resistor36) to the increase of the load voltage on the electrochemical deviceconjunctive body 8.

[0206] In such a manner, according to the circuit of FIG. 18, when theload voltage on the electrochemical device conjunctive body 8 is lowerthan a specified voltage, a large current can be supplied to theelectrochemical device conjunctive body 8. On the other hand, when theload voltage on the electrochemical device conjunctive body 8 is higherthan the specified voltage, a current smaller than the current when theload voltage on the electrochemical device conjunctive body 8 is lowerthan the specified voltage can be supplied to the electrochemical deviceconjunctive body 8. As a result, in the intermittent operation in thehigh humidity environment, significant reduction in the quantity ofconverted gas at the start of the operation of gas conversion isprevented with precision. In addition, a stable quantity of convertedgas can be obtained during the operation of gas conversion.

[0207] Next, description will be made on the operation of thisembodiment along a specific example while comparison is made withRelated Art Technique 2. Incidentally, the conditions of theintermittent operation and the conditions of the outside air environmentare similar to those in Embodiment 1 or 2. In the circuit of FIG. 18,for example, assuming that the operating voltage (Vz) of the constantvoltage diode 37 is 2.5 V, the AC input is 100 V at 60 cycles, thevoltage applied to the electrochemical device conjunctive body 8 by thevoltage limiting Zener diode 35 is 5 V, the value of a constant currentdetermined by the capacitor 34 is 75 mA/cm² ₁ and the resistance valueof the resistor 36 is 20 Ω, the load voltage on the electrochemicaldevice conjunctive body 8 is lower than 2.5 V at the start of theoperation of gas conversion. Thus, a constant current of 75 mA/cm² flowsinto the electrochemical device conjunctive body 8. As a result, avoltage exceeding 2V is applied to the electrochemical deviceconjunctive body 8 even at the start of the operation of gas conversion,so that the quantity of generated ozone is prevented from being loweredsignificantly.

[0208] After that, when the load voltage on the electrochemical deviceconjunctive body 8 increased to be not lower than 2.5 V, the currentflowing into the electrochemical device conjunctive body 8 decreased sothat the load voltage on the electrochemical device conjunctive body 8became substantially constant. At the same time, the value of thecurrent flowing into the electrochemical device conjunctive body 8 alsobecame substantially constant. Accordingly, a stable quantity ofgenerated ozone is obtained.

[0209] In such a manner, according to the circuit of FIG. 18, a largecurrent can be supplied to the electrochemical device conjunctive body 8when the operation of gas conversion is restarted. Thus, in theintermittent operation in the high humidity environment, significantreduction in the quantity of generated ozone at the restart of theoperation of gas conversion is prevented with precision. In addition,after that, a small current can be supplied the electrochemical deviceconjunctive body 8 so that a stable quantity of generated ozone can beobtained.

[0210] Incidentally, although examples using the constant voltage diodes137 and 52 are shown in Embodiments 11 and 12 shown in FIGS. 16 and 18respectively, a Zener diode making conduction with a constant voltagesimilar to that in each of these constant voltage diodes may be used.Also in this case, similar effects can be obtained.

[0211] In addition, description in the respective Embodiments 5, 7 and10 to 12 is made on the case where the operating voltage (Vz) of theconstant voltage diode 127, 137, 19, 37, 52 is set to 2.5 V. Theoperating voltage (Vz) is not limited to this value, but may be setproperly to make the load voltage on the electrochemical deviceconjunctive body 8 higher than 3 V.

[0212] In addition, description in the respective Embodiments 1 to 12 ismade on the case where the voltage (VO) of the DC power supply 6 or theoutput voltage determined by the Zener diode 35 is set to 5 V. Thevoltage (VO) of the DC power supply 6 or the output voltage determinedby the Zener diode 35 is not limited to this value, but may be combinedproperly with the operating voltage (Vz) of the constant voltage diode127, 137, 19, 37, 52 so as to make the load voltage on theelectrochemical device conjunctive body 8 higher than 3 V.

[0213] In addition, description in the respective Embodiments 1 to 10 ismade on the case where a current flowing into the electrochemical deviceconjunctive body 8 in the steady condition or a current flowing into theelectrochemical device conjunctive body 8 when the load voltage on theelectrochemical device conjunctive body 8 is larger than a specifiedvoltage is set to 25 mA/cm². The current is not limited to this value,but may be set to be smaller or larger in accordance with a requiredquantity of generated ozone. Incidentally, when there is a limit in thecapacity of the DC power supply 6, it is desired that the constantcurrent density is as small as possible.

[0214] In addition, in the respective Embodiments 1 to 10 and 12, whenthe load voltage on the electrochemical device conjunctive body 8 islower than a specified voltage, the current flowing into theelectrochemical device conjunctive body 8 is set to 75 mA/cm². Thecurrent is not limited to this value, but may be set properly to belarger than a constant current flowing in the steady condition. In thiscase, there is an advantage that a stable quantity of generated gas canbe obtained in a short time if the current flowing into theelectrochemical device conjunctive body 8 is increased. Thus, a largercurrent flows into the electrochemical device conjunctive body 8 so thatthe quantity of generated ozone increases.

[0215] In addition, description in Embodiments 1 to 12 is made on thecase where the high humidity environment is 25° C. in temperature and90% in relative humidity. The invention is not limited to thisenvironment, but similar effects can be obtained in the case whereenvironment has a higher temperature or humidity or in the case whereenvironment has a lower temperature or humidity, on the contrary.

[0216] In addition, in Embodiments 1, 2, 4, 5, 6, 8 and 10, a primarybattery such as a plurality of dry cells, a chargeable secondarybattery, or a circuit having a function to convert an AC voltage into aDC voltage may be used as the DC power supply 6.

[0217] (Embodiment 13)

[0218]FIG. 20 is a diagram for explaining the configuration of anelectrolytic gas converter according to Embodiment 13 of the invention.The invention associated with this embodiment is developed by findingthe following fact. Control is made to block the electrochemical deviceconjunctive body 8 perfectly from a control circuit during thesuspension of the operation of gas conversion. That is, control is madeto release a circuit connected to the electrochemical device conjunctivebody 8. Thus, stable performance can be obtained for a longer time.

[0219] In FIG. 20, the reference numeral 301 represents a relay; and302, a relay switch. The other configuration is similar to that in FIG.12 shown in Embodiment 8.

[0220] In this embodiment, a unit is constituted by the relay 301 andthe relay switch 302, so that the unit makes control in a manner suchthat a circuit connected to the electrochemical device conjunctive body8 is released during the suspension of the operation of gas conversion.

[0221] Next, description will be made on the operation. In the circuitof FIG. 20, at the start of the operation of gas conversion, the relay301 operates as soon as the power supply 6 operates. Thus, the relayswitch 302 is brought into the closed state (wire connection isconnected) so that the circuit of FIG. 20 operates. After that, when theoperation of the circuit of FIG. 20 is suspended, the relay 301 issuspended so that the relay switch 302 is brought into the opened state(wire connection is disconnected). Thus, by providing the relay 301 inthe circuit, the electrochemical device conjunctive body 8 can beblocked perfectly from the circuit when the circuit of FIG. 20 is insuspension. That is, the circuit connected to the electrochemical deviceconjunctive body 8 is released during the suspension of the operation ofgas conversion. Thus, stable performance could be obtained for a longertime.

[0222] Incidentally, description is made above on the case where therelay 301 and the relay switch 302 are provided in the electrolytic gasconverter according to Embodiment 8 shown in FIG. 12 for making controlso that the circuit connected to the electrochemical device conjunctivebody 8 is released during the suspension of the operation of gasconversion. The invention is not limited to this case, but may beapplied to another circuit having a circuit for controlling a voltageapplied to the electrochemical device conjunctive body 8 or a currentflowing into the electrochemical device conjunctive body 8. For example,in an electrolytic gas converter according to any one of Embodiments 1to 4, or in an electrolytic gas converter according to any one ofEmbodiments 9 to 12, the relay 301 and the relay switch 302 may beprovided to make control so that the circuit connected to theelectrochemical device conjunctive body 8 is released during thesuspension of the operation of gas conversion. In this case, similareffects can be obtained.

[0223] In addition, in a related-art electrolytic gas converter shown inFIG. 21 or an electrolytic gas converter shown in FIG. 2 or 6, the relay301 and the relay switch 302 may be provided to make control so that thecircuit connected to the electrochemical device conjunctive body 8 isreleased during the suspension of the operation of gas conversion. Inthis case, similar effects can be obtained.

[0224] Further, also in an electrolytic gas converter described inEmbodiments 5 to 7 and having a unit for making control so that avoltage low enough or a current small enough not to convert moistureinto gas is applied or conducted to the electrochemical deviceconjunctive body 8 during the suspension of the operation of gasconversion, there may be provided such a design that control is made sothat the circuit connected to the electrochemical device conjunctivebody 8 is released, for example, when the intermittent operation isstopped seasonally.

[0225] (Embodiment 14)

[0226] For example, when the electrochemical device conjunctive body 8is installed as an ozone generating device in electric equipment such asan air conditioner, a refrigerator or a dish washer, a circuit accordingto the invention shown in FIG. 1, FIG. 3, FIG. 4 to FIG. 14, FIG. 16 orFIG. 18, is used. Then, the circuit allows a predetermined current to besupplied to the electrochemical device conjunctive body 8 so that theozone concentration in such electric equipment becomes desired one.Thus, even in the intermittent operation in the high humidityenvironment, the quantity of generated gas can be prevented from beinglowered significantly at the start of the operation of gas conversion,while a stable quantity of generated ozone can be obtained during theoperation of gas conversion. Accordingly, predetermined ozoneconcentration can be obtained. In addition, the invention is not limitedto such electric equipment. Also when the electrochemical deviceconjunctive body 8 is installed in a car, a cleaner, a food container ora refuse container, effects similar to those in the case can beobtained.

[0227] In addition, also when the electrochemical device conjunctivebody 8 is used as a dehumidifying device, an oxygen generating device,or a hydrogen generating device, a circuit according to the inventionshown in FIG. 1, FIG. 3, FIG. 4 to FIG. 14, FIG. 16 or FIG. 18, is usedto supply a predetermined current to the electrochemical deviceconjunctive body 8. In this case, even in the intermittent operation inthe high humidity environment, a stable quantity of converted gas can beobtained.

[0228] Incidentally, when the electrochemical device conjunctive body 8is used as an ozone generating device, that is, when the electrolyticgas converter is an ozone generator, for example, an anode in whichβ-type or α-type lead dioxide is thinly electrodeposited on an expandedmetal substrate made of titanium and plated with platinum as undercoatis used as the anode 1 of the electrochemical device conjunctive body 8.As the cathode 2, for example, there is used a cathode in which a solidpolymer electrolyte obtained by liquefying carbon powder carryingplatinum fine particles is fixedly attached as binder onto a porouscarbon fiber substrate.

[0229] In addition, when the electrochemical device conjunctive body 8is used as an oxygen gas generating device or a dehumidifying device,that is, when the electrolytic gas converter is an oxygen gas generatoror a dehumidifier, for example, a porous expanded metal substrate madeof titanium and plated with platinum is used as the anode 1 of theelectrochemical device conjunctive body 8. In this case, oxygen isgenerated from the anode while water is released from the back of thecathode.

[0230] In addition, when the electrochemical device conjunctive body 8is used as a hydrogen generating device, that is, when the electrolyticgas converter is a hydrogen gas generator, for example, a porousexpanded metal substrate made of titanium and plated with platinum isused as each of the anode 1 and the cathode 2. In this case, hydrogengas is generated in the cathode.

[0231] As described above, according to the invention, there is provideda first electrolytic gas converter including: an electrochemical deviceconjunctive body having an anode and a cathode each having a catalystlayer provided on a substrate made of a conductive porous base material,and a solid polymer electrolyte membrane disposed between the anode andthe cathode, a DC voltage being applied to the electrochemical deviceconjunctive body so as to convert atmospheric moisture into ozone gas,oxygen gas or hydrogen gas; and a unit for making control so that anelectric current flows into the electrochemical device conjunctive bodyduring a predetermined period of time after start of operation of gasconversion, the electric current being larger than that after thepredetermined period of time passes. Accordingly, in the intermittentoperation in the high humidity environment, the quantity of convertedgas is prevented from being lowered significantly at the start of theoperation of gas conversion, while a stable quantity of converted gascan be obtained during the operation of gas conversion.

[0232] Further, according to the invention, there is provided a secondelectrolytic gas converter in which in the first electrolytic gasconverter, a unit is provided for making control so that an electriccurrent is made to flow into the electrochemical device conjunctive bodyperiodically during a predetermined period of time after start ofoperation of gas conversion, the electric current being larger than thatafter the predetermined period of time passes. Accordingly, in theintermittent operation in the high humidity environment, the quantity ofconverted gas is prevented from being lowered significantly at the startof the operation of gas conversion, while a stable quantity of convertedgas can be obtained during the operation of gas conversion.

[0233] Further, according to the invention, there is provided a thirdelectrolytic gas converter in which in the first electrolytic gasconverter, a unit is provided for making control so that a predeterminedconstant electric current flows into the electrochemical deviceconjunctive body after the predetermined period of time passes since thestart of operation of gas conversion. Accordingly, the quantity ofconverted gas can be obtained efficiently and stably without generatingexcessive gas even if there is a change in the environmental conditions.Thus, the stability of the quantity of converted gas is more improved.

[0234] Further, according to the invention, there is provided a fourthelectrolytic gas converter including: an electrochemical deviceconjunctive body having an anode and a cathode each having a catalystlayer provided on a substrate made of a conductive porous base material,and a solid polymer electrolyte membrane disposed between the anode andthe cathode, a DC voltage being applied to the electrochemical deviceconjunctive body so as to convert atmospheric moisture into ozone gas,oxygen gas or hydrogen gas; and a unit for making control so that avoltage low enough or an electric current small enough not to convertthe moisture into the gas is applied or conducted to the electrochemicaldevice conjunctive body during suspension of operation of gasconversion. Accordingly, in the intermittent operation in the highhumidity environment, the quantity of converted gas is prevented frombeing lowered significantly at the start of the operation of gasconversion, while a stable quantity of converted gas can be obtainedduring the operation of gas conversion.

[0235] Further, according to the invention, there is provided a fifthelectrolytic gas converter in which in the fourth electrolytic gasconverter, a unit is provided for making control so that a predeterminedconstant electric current flows into the electrochemical deviceconjunctive body during the operation of gas conversion. Accordingly,the quantity of converted gas can be obtained efficiently and stablywithout generating excessive gas even if there is a change in theenvironmental conditions. Thus, the stability of the quantity ofconverted gas is more improved.

[0236] Further, according to the invention, there is provided a sixthelectrolytic gas converter including: an electrochemical deviceconjunctive body having an anode and a cathode each having a catalystlayer provided on a substrate made of a conductive porous base material,and a solid polymer electrolyte membrane disposed between the anode andthe cathode, a DC voltage being applied to the electrochemical deviceconjunctive body so as to convert atmospheric moisture into ozone gas,oxygen gas or hydrogen gas; and a unit for making control so that anelectric current is made to flow into the electrochemical deviceconjunctive body in a case where a voltage applied to theelectrochemical device conjunctive body is lower than a predeterminedvoltage, the electric current being larger than in another case wherethe voltage is higher than the predetermined voltage. Accordingly, inthe intermittent operation in the high humidity environment, thequantity of converted gas is prevented from being lowered significantlyat the start of the operation of gas conversion, while a stable quantityof converted gas can be obtained during the operation of gas conversion.

[0237] Further, according to the invention, there is provided a seventhelectrolytic gas converter in which in the sixth electrolytic gasconverter, a unit is provided for making control so that a predeterminedconstant electric current is made to flow into the electrochemicaldevice conjunctive body when a voltage applied to the electrochemicaldevice conjunctive body is not lower than a predetermined voltage.Accordingly, the quantity of converted gas can be obtained efficientlyand stably without generating excessive gas even if there is a change inthe environmental conditions. Thus, the stability of the quantity ofconverted gas is more improved.

[0238] Further, according to the invention, there is provided an eighthelectrolytic gas converter in which in the first or sixth electrolyticgas converter, a unit is provided for making control so that a circuitconnected to the electrochemical device conjunctive body is releasedduring suspension of operation of gas conversion. Accordingly, a stableperformance can be obtained for a longer time.

[0239] Further, according to the invention, there is provided a ninthelectrolytic gas converter in which in the any one of the first througheighth electrolytic gas converters, the electrochemical deviceconjunctive body is used as an ozone generating device, an oxygengenerating device, a hydrogen generating device, or a dehumidifyingdevice. Accordingly, in the intermittent operation in the high humidityenvironment, the quantity of generated ozone, oxygen and hydrogen gas orthe humidified quantity is prevented from being lowered significantly atthe start of the operation of gas conversion, while a stable quantity ofgenerated ozone, oxygen and hydrogen gas or a stable humidified quantitycan be obtained during the operation of gas conversion.

[0240] Further, according to the invention, there is provided firstelectric equipment having any one of the first through eighthelectrolytic gas converters. Accordingly, in the intermittent operationin the high humidity environment, the quantity of converted gas isprevented from being lowered significantly at the start of the operationof gas conversion, while a stable quantity of converted gas can beobtained during the operation.

What is claimed is:
 1. An electrolytic gas converter comprising: anelectrochemical device conjunctive body having an anode and a cathodeeach having a catalyst layer provided on a substrate made of aconductive porous base material, and a solid polymer electrolytemembrane disposed between said anode and said cathode, a DC voltagebeing applied to said electrochemical device conjunctive body so as toconvert atmospheric moisture into ozone gas, oxygen gas or hydrogen gas;and a unit for controlling so that an electric current flows into saidelectrochemical device conjunctive body during a predetermined period oftime after start of operation of gas conversion, the electric currentbeing larger than that after the predetermined period of time passes. 2.The electrolytic gas converter according to claim 1, further comprising:a unit for controlling so that an electric current flows into saidelectrochemical device conjunctive body periodically during apredetermined period of time after start of operation of gas conversion,the electric current being larger than that after the predeterminedperiod of time passes.
 3. The electrolytic gas converter according toclaim 1, further comprising: a unit for controlling so that apredetermined constant electric current flows into said electrochemicaldevice conjunctive body after the predetermined period of time passessince the start of operation of gas conversion.
 4. An electrolytic gasconverter comprising: an electrochemical device conjunctive body havingan anode and a cathode each having a catalyst layer provided on asubstrate made of a conductive porous base material, and a solid polymerelectrolyte membrane disposed between said anode and said cathode, a DCvoltage being applied to said electrochemical device conjunctive body soas to convert atmospheric moisture into ozone gas, oxygen gas orhydrogen gas; and a unit for controlling so that a voltage low enough oran electric current small enough not to convert the moisture into thegas is applied or conducted to said electrochemical device conjunctivebody during suspension of operation of gas conversion.
 5. Theelectrolytic gas converter according to claim 4, further comprising: aunit for controlling so that a predetermined constant electric currentflows into said electrochemical device conjunctive body during theoperation of gas conversion.
 6. An electrolytic gas convertercomprising: an electrochemical device conjunctive body having an anodeand a cathode each having a catalyst layer provided on a substrate madeof a conductive porous base material, and a solid polymer electrolytemembrane disposed between said anode and said cathode, a DC voltagebeing applied to said electrochemical device conjunctive body so as toconvert atmospheric moisture into ozone gas, oxygen gas or hydrogen gas;and a unit for controlling so that an electric current flows into saidelectrochemical device conjunctive body in a case where a voltageapplied to said electrochemical device conjunctive body is lower than apredetermined voltage, the electric current being larger than in anothercase where the voltage is higher than the predetermined voltage.
 7. Theelectrolytic gas converter according to claim 6, further comprising: aunit for controlling so that a predetermined constant electric currentflows into said electrochemical device conjunctive body when a voltageapplied to said electrochemical device conjunctive body is not lowerthan a predetermined voltage.
 8. The electrolytic gas converteraccording to claim 1, further comprising: a unit for controlling so thata circuit connected to said electrochemical device conjunctive body isreleased during suspension of operation of gas conversion.
 9. Theelectrolytic gas converter according to claim 1, wherein saidelectrochemical device conjunctive body is used as an ozone generatingdevice, an oxygen generating device, a hydrogen generating device, or adehumidifying device.
 10. Electric equipment comprising an electrolyticgas converter according to claim
 1. 11. The electrolytic gas converteraccording to claim 4, further comprising: a unit for controlling so thata circuit connected to said electrochemical device conjunctive body isreleased during suspension of operation of gas conversion.
 12. Theelectrolytic gas converter according to claim 4, wherein saidelectrochemical device conjunctive body is used as an ozone generatingdevice, an oxygen generating device, a hydrogen generating device, or adehumidifying device.
 13. Electric equipment comprising an electrolyticgas converter according to claim
 4. 14. The electrolytic gas converteraccording to claim 6, further comprising: a unit for controlling so thata circuit connected to said electrochemical device conjunctive body isreleased during suspension of operation of gas conversion.
 15. Theelectrolytic gas converter according to claim 6, wherein saidelectrochemical device conjunctive body is used as an ozone generatingdevice, an oxygen generating device, a hydrogen generating device, or adehumidifying device.
 16. Electric equipment comprising an electrolyticgas converter according to claim 8.